A portion of the disclosure of this patent document contains command formats and other computer language listings, all of which are subject to copyright protection. The copyright owner, EMC Corporation, has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
The invention relates generally to handling of data in a data storage environment, and more particularly to a system and method for reading a track of data to be backed up in order to improve performance of a backup operation in a data storage environment.
As is known in the art, computer systems which process and store large amounts of data typically include a one or more processors in communication with a shared data storage system in which the data is stored. The data storage system may include one or more storage devices, usually of a fairly robust nature and useful for storage spanning various temporal requirements, e.g. disk drives. The one or more processors perform their respective operations using the storage system. To minimize the chance of data loss, the computer systems also can include a backup storage system in communication with the primary processor and the data storage system. Often the connection between the one or more processors and the backup storage system is through a network in which case the processor is sometimes referred to as a xe2x80x9cbackup client.xe2x80x9d
The backup storage system can include a backup storage device (such as tape storage or any other storage mechanism), together with a system for placing data into the storage device and recovering the data from that storage device. To perform a backup, the client copies data from the shared storage system across the network to the backup storage system. Thus, an actual data file may be communicated over the network to the backup storage device.
The shared storage system corresponds to the actual physical storage. For the client to write the backup data over the network to the backup storage system, the client first converts the backup data into file data i.e., the client retrieves the data from the physical storage system level, and converts the data into application level format (e.g. a file) through a logical volume manager level, a file system level and the application level. When the backup storage device receives the data file, the backup storage system can take the application level data file, and convert it to its appropriate file system level format for the backup storage system. The data can then be converted through the logical volume manager level and into physical storage.
It has been recognized that it is a disadvantage for data that is involved in a backup operation to be unavailable for a host application, such as a database, to perform operations such as reads or writes. There have been remedies to such a problem in the prior art, but what is needed is resolution of such a problem with minimal to no effect on the host application, or to the data storage system itself, and also while allowing multiple backup sessions of the same data (or at least copies of the data) to occur, and while providing a straight-forward and fast performing solution.
In order to solve the problems of the prior art mentioned above, the present invention is a system and method for managing data involved with a host requested backup session.
The method of this includes enabling a data engine to be responsive to a host request to backup data stored in a data storage system by selectively reading the requested data, assigning a protected status for the read data; and allowing access to the read data for one or more host backup sessions that may occur subsequent to the first backup session until the protected status is changed to an unprotected status. Further embodiments of the method include allowing access to the data for a host I/O operation until the protected, status is changed to an unprotected status.
In an alternative embodiment, the invention includes a system for carrying out embodiments of the method steps. In another alterative embodiment, the invention includes a program product for carrying out embodiments of the method steps. In still another alternative embodiment the invention includes an apparatus enabled to carry out embodiments of the method steps.